How to Prep for Laying a Patio or Path
From: DK - Do It Yourself Home Improvement
Just as walls require sound foundations for construction, surfaces such as patios, paths and driveways also require a firm base. Foundation depth and type is purely dependent on whether the area will be used only for walking on, or whether cars will be driving or parking on it. Other considerations include the need for adequate drainage, so that water is channeled away from the surface, and away from any walls and the house. As well as being functional, paths and patios have a role in garden design and are often made of decorative materials.
Designing Paths and Patios
You may already have a clear idea of where you want a path to lead or a patio to be situated, but take time to consider your options. As well as taking into account the hard landscaping itself, think about how the layout and materials fit in with the overall design and style of your house and garden. If your garden has an informal style, consider including some areas for planting, and staggering paving materials to soften straight lines. For a more formal area, choose geometric shapes to carry on the theme.
Privacy is a key concern when planning a patio, because both you and your neighbors will probably prefer not to be overlooked. The exposure of a seating area is also important—a south- or west-facing area receives the most sun during the day and early evening.
You can use garden paths to lead the eye to a focal point and to create interest, or they can be purely for access. Your choice will influence your design—a decorative path might take a winding route, while an access route is more likely to follow a straight line. You can use a single material to create paths, or mix different surfaces. Consider laying slabs or pavers in different patterns.
Hard-landscaped areas are generally designed with some form of edging. If you are making a gravel path or using slabs or pavers laid dry on a sand bed, the edging will help prevent any lateral movement of the surface. Even if the slabs or pavers are bedded into mortar, an edge of some type provides the neatest finish. If a hard-landscaped area abuts a lawn, the edging should be lower than the lawn, so that you can mow over it. Treated lumber can be used or edging blocks bedded into a mortar strip. Treated lumber is the most straightforward to work with, does not require mortar and provides instant guidelines for leveling across a site.
Never seal over any utility covers or other access points to underground services with any kind of hard landscaping. Either build around them or, if they are set very low, create an easily removable and well-marked panel in the surface above or raise the cover itself on a course of bricks. Engineering bricks are ideal for building up the level of a utility cover because of their strength.
The top of an area of hard landscaping that abuts the house must be at least 4 inches below the damp-proof course in a masonry house wall. Any higher than this and splashes from falling rain can bridge the course and cause water problems inside.
Laying Pavers and Slabs
The pattern chosen for laying slabs or pavers is very much a personal choice. Manufacturers often provide good displays or brochures showing the various options. Some simple types of paver and slab design are shown below. Also remember that bricks can be used for paving. You can also buy cut or curved slabs to create alternative designs. Cutting such a curve yourself is practically impossible. Don't forget that you can also pave areas with any combination of pavers, slabs, gravel and cobbles.
Examples of Pavers
Examples of Slabs
You will need drainage around the edge of large hard-landscaped areas. Standing water near the house may soak into walls and cause mildew. Water on a paved surface can lead to the growth of algae and vegetation, making it slippery and dangerous—a problem for paving laid on a concrete slab or if mortar has been used. If pavers have been bedded onto sand, some water will drain down through joints and into the subsoil below. Always lay paths and patios with a very slight slope running away from adjacent walls.
Establishing a Slope
Over a small area, you can establish a slope to aid drainage by reducing the amount of mortar or sand under slabs or pavers as you move away from the house. For larger areas of hard landscaping, establish the correct slope in the foundations. A slope of 1 inch in 6 feet is sufficient.
Paths and paved areas that will take the weight of vehicles will need more extensive foundations than those used only by people. When planning a major project like a new driveway, seek professional advice about the foundations.
If you are laying slabs for a path or patio that will not be driven on, they can be laid directly on a compacted subsoil base. If the base has been recently disturbed by excavation work—for example, if an extension has been recently built—lay a crushed stone base on the compacted soil. The slabs may then be dry laid onto a sand layer or laid on mortar. The excavation depth will vary. Ideally, crushed stone should be 4 in (100 mm) deep. Slabs can also be laid on an old concrete surface without any excavation.
Foundation requirements for pavers are similar to those of slabs for paths and patios. However, for driveways and parking areas, pavers do not need a concrete base. They can be laid on compacted crushed stone covered with sand.
Square Paths and Patios
Use strings and pegs to lay out an area for a square patio area
Planning a Path
For straight guide lines, use string and pegs. A garden hose is ideal for planning curves in a design.
Copyright 2009 Dorling Kindersley Limited
Text copyright 2009 Julian Cassell and Peter Parham